AS3 TextField未应用标记

var t:TextField = new TextField();
t.text = \"this is bold\";

var f:TextFormat = new TextFormat();
f.bold = true;

t.setTextFormat(f, 0, 4); // start at character 0, end at character 4

addChild(t);

/**
 * Render a given portion of a String as bold
 * @param field The target TextField
 * @param needle The section of text to render bold
 */
function bolden(field:TextField, needle:String):void
{
    var tf:TextFormat = new TextFormat();
    tf.bold = true;

    var pos:uint = field.text.indexOf(needle);
    field.setTextFormat(tf, pos, pos + needle.length);
}


// example below
var t:TextField = new TextField();
t.text = \"i like iced tea\";

bolden(t, \"iced\");

addChild(t);

/**
 * Apply <b> tags
 * @param field The target TextField
 */
function bolden(field:TextField):void
{
    var tf:TextFormat = new TextFormat();
    tf.bold = true;

    var pos:int = 0;
    var cls:int = 0;

    while(true)
    {
        pos = field.text.indexOf(\"<b>\", pos);
        cls = field.text.indexOf(\"</b>\", pos);

        if(pos == -1) break;

        field.setTextFormat(tf, pos+3, cls);
        pos = cls;
    }
}


// example below
var t:TextField = new TextField();

t.width = stage.stageWidth;
t.htmlText = \"i like <b>iced</b> tea and <b>showbags</b>\";

bolden(t);

addChild(t);

textfield.setTextFormat(textformat);
if(xmlText.search(\'<b>\')){
    textformat.bold = true;
}

textfield.setTextFormat(textformat);
textformat.bold = true;